The Family History of Developmental Stuttering: A Scoping Review.

BACKGROUND: A positive family history is a significant risk factor for developmental stuttering. However, the reported rates of positive family histories are inconsistent across studies, making it difficult to synthesise the findings. AIM: This scoping review aimed to systematically map the literature on family histories of stuttering to clarify the reported stuttering proportions and identify methodological trends and gaps. METHOD & PROCEDURES: We conducted a literature search of PubMed, Web of Science, and PsycINFO on 4 February 2025. Two authors independently screened the records in two stages: first by title and abstract, and then by full text. OUTCOMES & RESULTS: We reviewed 19 studies that reported family histories of participants with developmental stuttering. Basic study characteristics such as sample size and country were extracted, and descriptive statistics, including family history rates, were calculated for quantitative data. A key finding was the wide variability in the reported proportion of individuals with a positive family history, ranging from 20.0% to 90.9%. This variability was strongly associated with inconsistencies in methodology, including the scope of relatives considered, the definition of stuttering within the family, and data collection methods. CONCLUSIONS & IMPLICATIONS: This review found that methodological variability appeared to be the primary factor contributing to the wide variation in reported rates in the research on family histories of stuttering. The findings suggest the need for rigorous research approaches to obtain a more comprehensive understanding of this phenomenon. WHAT THIS PAPER ADDS: What is already known on this subject A positive family history is widely recognized as a major risk factor for developmental stuttering, and genetic evidence suggests a strong heritable component. However, reported proportions of individuals with a family history of stuttering vary substantially across studies, making it difficult to synthesize the evidence and interpret findings consistently. What this study adds to the existing knowledge This scoping review systematically mapped 19 studies and revealed that reported rates of positive family history range widely from 20.0% to 90.9%. The review identifies key sources of methodological variability as primary contributors to this inconsistency. These findings highlight the need for greater clarification when defining and assessing family history in stuttering research. What are the potential clinical implications of this study? Clinicians and researchers may benefit from using clearer criteria and consistent reporting frameworks, which could support more accurate risk evaluation and better integration of genetic, epidemiological, and clinical evidence.